安徽某铁矿不同矿山废水库中微生物群落结构特征

【目的】研究安徽某铁矿不同矿山废水库中微生物群落结构特征及其影响因素。【方法】对比分析了该铁矿3个大型废水库的地球化学特征,并用高通量测序技术研究了水体中微生物群落组成,进而用统计学方法解析了环境因子对微生物群落结构的影响。【结果】3个废水库中有2个为酸性,1个为中性,理化性质有明显的差异。近年形成的塌方采场废水库(TF) pH仅为2.55±0.01,Fe浓度高达154.95±0.78mg/L,SO_4~(2–)浓度为3374.86±3.81mg/L;形成于20世纪70年代的排土场废水库(PT)酸性略弱(pH 2.9±0.02),Fe浓度(34.57±4.00 mg/L)与TF相比明显降低,SO_4~(2–)浓度则高达10398.98±626.70 mg/L;东沙采场废水库(DS)则为中性(pH7.55),但SO_4~(2–)仍高达4162.99mg/L,主要的金属离子为Mg(594.90 mg/L)、Ca (650.10 mg/L)。3个废水库的原核生物多样性随pH的升高而升高。两个酸性废水库的原核生物组成较为接近,但TF的化能自养菌含量较高(69.54%±2.89%),PT的化能异养菌含量较高(64.45%±13.81%)。自养铁氧化菌Ferrovum在TF中的比例高达(64.17±1.84)%,在PT中则下降为(35.39±13.74)%。但PT中含有丰富的化能异养嗜酸菌如Acidicapsa(15.75%±3.99%)、Acidiphilium(10.65%±2.05%)、Acidisphaera (6.34%±1.02%)等。DS中虽然也含有较高的金属离子和SO_4~(2–),但其中的原核生物组成与TF和PT截然不同,主要为Limnohabitans (18.47%)、Rhodobacter (8.42%)等。3个废水库的真核生物群落主要由藻类组成,酸水库TF和PT中主要为棕鞭藻属(Ochromonas)和胶球藻属(Coccomyxa),棕鞭藻属在TF中(53.65%±2.02%)占优势,胶球藻属在PT中(68.84±10.4%)占优势,中性废水库DS中则主要是小环藻属(Cyclotella)(49.85%)。经统计学分析,pH是影响矿山废水微生物多样性和群落组成的主要环境因素。     

紫金山铜矿酸性矿山废水微生物群落多样性

【背景】为避免环境污染,酸性矿山废水需经处理后才能排放,处理后的废水理化性质会发生显著变化,将影响整个微生物群落的结构。【目的】分析处理前后的细菌和真菌群落变化及其与理化参数的关系,为矿山废水的处理提供参考指标,并为矿山污染场地的修复提供理论基础。【方法】采集福建紫金山铜矿的酸性矿山废水并测定其理化性质。采用基于原核微生物16S rRNA基因V4区和真菌18S rRNA基因ITS的高通量测序技术分析水样的微生物群落结构。【结果】经中和处理后的回水与矿坑水和生物浸出液相比,pH升高,重金属离子含量显著降低。原核微生物的多样性高于真菌,回水的物种多样性高于矿坑水和浸出液。回水中变形菌门的丰度最高,矿坑水和浸出液中分别以广古菌门和硝化螺菌门的丰度最高。回水中噬氢菌属为优势类群,矿坑水和浸出液中的优势菌是钩端螺旋菌属,铁质菌属等古菌也有一定的比例。pH、Al、Mn、Zn与回水中相对丰度较高的菌属显著相关,而矿坑水和浸出液中的高丰度类群与环境因子没有显著的相关性。【结论】研究表明酸性废水的中和沉淀处理对微生物群落产生了较大的影响,微生物群落变化可以作为矿山酸性废水污染处理效果的一个参考指标。     

Diversity of Prokaryotic Communities Indigenous to Acid Mine Drainage and Related Rocks from Baiyin Open-Pit Copper Mine Stope,China

Metagenomic approach permits us to obtain the latent resources from culturable and unculturable microorganisms in ecosystem. In this study, high-throughput sequencing was practiced to comprehensively probe prokaryotic community within extreme acidic environment of Baiyin open-pit mine stope, which varied in pH and other physicochemical parameters. Bioinformatics analysis was further accomplished to process millions of Illumina reads and analyzed alpha and beta diversities, and prokaryotic community profile in different samples obtained from the acidic mine stope. Diversity indices such as ACE, Chao, Shannon, and Simpson were varied among samples. Both taxon richness and evenness were significantly higher in the solid samples than that of the water samples. Taxonomic diversity was unexpectedly higher within confined pit ecosystem. Most of the sequences were assigned to phyla Proteobacteria, Firmicutes, and Acidobacteria. In archaea, Euryarchaeota and Thaumarchaeota were major phyla reported, however, archaea occupied very little share in the metagenome. At class level, variation in community structure was higher within samples. Among iron- and sulfur-related acidophiles, 30.8% of the sequences were unidentified at genera level, while the remaining were dominated by sulfur and/or iron oxidizing Acidithiobacillus and heterotrophic Acidiphilum related groups. The community profile of solid and water groups was different and metagenomic biomarkers were higher in solid, while acidophiles and archaea were reported only in water group by using LEfSe. Among samples, community structure and abundance was varied in terms of OTUs abundance, which clearly indicates spatial variation and proposed the influence of physicochemical and geochemical properties on phylogenetic diversity. This study offers numerous treasured datasets for better understanding the community composition under the influence of geochemical and physicochemical factors and possible novelty in terms of taxonomic/phylogenetic diversity in acidic ecosystem.     

Distribution and Diversity of Cyanobacteria and Eukaryotic Algae in Qinghai–Tibetan Lakes

Cyanobacteria and eukaryotic algae are important primary producers in a variety of environments, yet their distribution and response to environmental change in saline lakes are poorly understood. In this study, the community structure of cyanobacteria and eukaryotic algae in the water and surface sediments of six lakes and one river on the Qinghai–Tibetan Plateau were investigated with the 23S rRNA gene pyrosequencing approach. Our results showed that salinity was the major factor controlling the algal community composition in these aquatic water bodies and the community structures of water and surface sediment samples grouped according to salinity. In subsaline–mesosaline lakes (salinity: 0.5–50 g L^?1), Cyanobacteria (Cyanobium, Synechococcus) were highly abundant, while in hypersaline lakes (salinity: >50 g L^?1) eukaryotic algae including Chlorophyta (Chlorella, Dunaliella), Bacillariophyta (Fistulifera), Streptophyta (Chara), and Dinophyceae (Kryptoperidinium foliaceum) were the major members of the community. The relative abundance ratio of cyanobacteria to eukaryotic algae was significantly correlated with salinity. The algae detected in Qinghai–Tibetan lakes exhibited a broader salinity range than previously known, which may be a result of a gradual adaptation to the slow evolution of these lakes. In addition, the algal community structure was similar between water and surface sediment of the same lake, suggesting that sediment algal community was derived from water column.     

Archaeal and bacterial communities of heavy metal contaminated acidic waters from zinc mine residues in Sepetiba Bay

Mining of metallic sulfide ore produces acidic water with high metal concentrations that have harmful consequences for aquatic life. To understand the composition and structure of microbial communities in acid mine drainage (AMD) waters associated with Zn mine tailings, molecular diversity of 16S genes was examined using a PCR, cloning, and sequencing approach. A total of 78 operational taxonomic units (OTUs) were obtained from samples collected at five different sites in and around mining residues in Sepetiba Bay, Brazil. We analyzed metal concentration, physical, chemical, and microbiological parameters related to prokaryotic diversity in low metal impacted compared to highly polluted environments with Zn at level of gram per liter and Cd–Pb at level of microgram per liter. Application of molecular methods for community structure analyses showed that Archaea and Bacteria groups present a phylogenetic relationship with uncultured environmental organisms. Phylogenetic analysis revealed that bacteria present at the five sites fell into seven known divisions, α-Proteobacteria (13.4%), β-Proteobacteria (16.3%), γ-Proteobacteria (4.3%), Sphingobacteriales (4.3%), Actinobacteria (3.2%) Acidobacteria (2.1%), Cyanobacteria (11.9%), and unclassified bacteria (44.5%). Almost all archaeal clones were related to uncultivated Crenarchaeota species, which were shared between high impacted and low impacted waters. Rarefaction curves showed that bacterial groups are more diverse than archaeal groups while the overall prokaryotic biodiversity is lower in high metal impacted environments than in less polluted habitats. Knowledge of this microbial community structure will help in understanding prokaryotic diversity, biogeography, and the role of microorganisms in zinc smelting AMD generation and perhaps it may be exploited for environmental remediation procedures in this area.     

安徽某铁矿酸性矿山废水中真核生物的群落结构特征

【目的】研究酸性矿山废水中真核生物的群落结构特征以及群落结构与环境因子之间的关系。【方法】利用分子生物学方法,通过构建18S rRNA基因克隆文库进行系统发育分析;利用典范对应分析(CCA)方法解析环境因子对真核生物群落结构的影响。【结果】系统发育分析表明:子囊菌门(Ascomycota)普遍存在于4个样品中,并在样品1和样品3中占统治地位,而绿藻门(Chlorophyta)和担子菌门(Basidiomycota)分别为样品2和样品4的优势类群。该酸性矿山废水中的克隆与许多已知的耐酸耐重金属真核生物亲缘关系较近,如Sarcinomyces petricola、Penicillium janthinellum、Coniochaeta velutina、Trichoderma viride、Chlorellaprotothecoides var.acidicola、Ochromonas sp.等。此外,样品中还存在大量的已知人类病原菌,如Lecythophorahoffmannii、Cryptococcus neoformans。CCA分析表明:TN、SO24-、Fe2+、Eh是影响真核生物群落空间分布的主要因素。【结论】所研究的酸性矿山废水中真核生物的群落结构在时间和空间上均有较大差异,这可能与水体的理化性质有关;高含量人类致病菌的存在是之前研究所未发现的;酸性环境中真核生物的生态学研究有助于开发高效处理酸性矿山废水的方法。     

Green algae in tundra soils affected by coal mine pollutions

Green algal communities were investigated in clean and pollution-impacted tundra soils around the large coal mine industrial complex of Vorkuta in the E. European Russian tundra. Samples were collected in three zones of open-cast coal mining with different degrees of pollution-impacted soil transformation. A total of 42 species of algae were found in all zones. The species richness decreased from 27 species in undisturbed zones to 19 species in polluted zones. Under open-cast coal mining impacts the community structure simplified, and the dominant algae complexes changed. Algae that are typical for clean soils disappeared from the communities. The total abundance of green algae (counted together with Xanthophyta) ranged between 100–120 × 10³ (cells/g dry soils) in undisturbed zones and 0.5–50 × 10³ in polluted zones. Soil algae appear to be better indicators of coal mine technogenic pollution than flowering plants and mosses. Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia.     

Coal mine drainage effects on a lotic ecosystem in Northwest Colorado,U.S.A.

An aquatic biological survey was conducted in 1979–1980 to determine the effects of drainage from an active coal strip-mine on Trout Creek, in northwest Colorado, U.S.A. Sampling was conducted over four seasons at four stations for periphyton, benthic invertebrates and fish. Periphyton in Trout Creek changed in the relative abundance of algae divisions in no apparent relation to mining. Diatoms were the predominant division at all sites. Golden-brown algae were abundant in spring at the stations upstream and adjacent to the mine. Blue-green algae were relatively important at stations upstream and downstream of the mine in winter. Benthic invertebrates exhibited a progressive increase in density, biomass and number of taxa from the upstream station to the downstream station. Shannon-Wiener diversity index for bethic invertebrates decreased slightly downstream of mine drainage but remained indicative of a clean water community. Aquatic insects (especially Trichoptera) were the predominant invertebrates at all stations. Analysis of functional groups of benthic invertebrates revealed increased importance of collector species at the lower sites while shredders were most important upstream of the mine. Unlike the invertebrates, fish exhibited slightly lower biomass at the station adjacent to the mine. The decrease was due to fewer salmonids. However, salmonid density and biomass increased substantially at the station just downstream of the mine. Non-game species (suckers and minnows) increased in numbers downstream and were most abundant at the lowest station. This coal strip-mine had little discernable adverse effects on the periphyton and invertebrates of Trout Creek. Fish populations did not appear to be significantly affected by the mine. Apparently, the presence of settling ponds and a buffer zone of unmined land between the mine and the stream helped to minimize adverse effects.     

Microbial Communities in Chesapeake & Ohio Canal National Historical Park and Their Function as Indicators of Water Quality

Abstract

The objective of this study was to establish meaningful relationships between prokaryotic community profiles and water quality parameters in different water bodies (spring, stream, cave, and mine) in the middle reach of the Chesapeake & Ohio Canal National Historic Park (C&O), Maryland. The microbial profiles in the water samples were determined using metagenomic analysis. The relationships between microbial phylogenetic profiles and water quality parameters were investigated using principal component analysis (PCA) and redundancy analysis (RDA). The most abundant phyla identified in most samples were Proteobacteria (55.4%), Bacteroidetes (12.3%), Actinobacteria (10.6%), Firmicutes (2.4%), Planktomycetes (1.8%), Verrucomicrobia (1.5%), Chloroflexi (1.5%), and Acidobacteria (1.3%), which are major bacterial and archaeal groups typically observed in natural freshwater environments. PCA showed that water chemistry was determined primarily by the geology of the site and the type of water source (i.e., spring, stream, cave, or mine). Most samples located in carbonate formations correlated with high alkalinity, inorganic carbon, and calcium, representing the typical karstic geochemistry. RDA shows that pH, electrical conductivity, temperature and nutrients including nitrate, phosphate, and sulfate, were significant determinants of the microbial ecology.     

Seasonal and spatial variations in microbial community structure and diversity in the acid stream draining across an ongoing surface mining site

This study examined the microbial community in an acidic stream draining across the Yun-Fu pyrite mine (Guangdong, China), where extremely acidic mine water is a persistent feature due to the intensive surface mining activities. Analysis of terminal restriction fragment length polymorphism (TRFLP) of 16S rRNA gene sequences showed that microbial populations varied spatially and seasonally and correlated with geochemical and physical conditions. After the stream moves from underground to the surface, the microbial community in the acidic water rapidly evolves into a distinct community close to that in the downstream storage pond. Comparisons of TRFLP peaks with sequenced clone libraries indicated that bacteria related to the recently isolated iron-oxidizer Ferrovum myxofaciens dominated the acidophilic community throughout the year except for the samples collected in spring from the storage pond, where Ferroplasma acidiphilum -like archaea represented the most abundant group. Acidithiobacillus ferrooxidans -affiliated organisms increased along the acid stream and remained common over the year, whereas Leptospirillum ferrooxidans -like bacteria were negligible or even not detected in the analyzed samples. The data indicate that changes in environmental conditions are accompanied by significant shifts in community structure of the prokaryotic assemblages at this opencast mining site.     

Characteristics of softwater streams in Rhode Island II. Composition and seasonal dynamics of macroalgal communities

Forty stream segments in Rhode Island, U.S.A., were examined seasonally from June 1979 to March 1982. Thirty-nine species of macroalgae were collected, respresenting 25 genera. The composition of the lotic flora was 54% green algae, 31% red algae, 5% blue-green algae, 5% xanthophytes, 3% chrysophytes and 3% diatoms. The majority of these taxa (85%) were filamentous. From a biweekly examination of five stream segments, macroalgal communities could be grouped according to light regime. Species in unshaded streams exhibited little seasonality, whereas in streams shaded by one or more layers of riparian canopy, maxima in species numbers and abundance occurred during colder seasons. The most widespread and abundant species were the blue-green alga Phormidium retzii, the green alga Draparnaldia acuta, and the diatom Eunotia pectinalis. P. retzii and E. pectinalis were aseasonal annuals, while D. acuta was primarily a winter-spring form. It appears that pH is a major factor affecting broad geographic distribution patterns of stream macroalgae, whereas the light regime established by overhanging canopy is an important factor which influences localized abundance and seasonality of lotic macroalgal communities. Niche pre-emption appears to be a common mode of resource space division among stream macroalgae in Rhode Island. E. pectinalis is the strongly developed dominant in this drainage system.     

Occurrence and phylogenetic significance of cytokinesis-related callose in green algae, bryophytes, ferns and seed plants

 In order to investigate the occurrence of callose in dividing cells, we cultivated a selection of 30 organisms (the prokaryotic cyanobacterium Anabaena and eukaryotic green algae, bryophytes, ferns and seed plants) under defined conditions in the laboratory. Samples from these photoautotrophs, which are members of the evolutionary 'green lineage' leading from freshwater algae to land plants, were analysed by fluorescence microscopy. The β-1,3-glucan callose was identified by its staining properties with aniline blue and sirofluor. With the exception of the prokaryotic cyanobacterium, all of the eukaryotic organisms studied were capable of producing wound-induced callose. No callose was detected during cytokinesis of dividing cells of unicellular green algae (and Anabaena). However, in all of the multicellular green algae and land plants (embryophytes) investigated, callose was identified in newly made septae by an intense yellow fluorescence. The formation of wound callose was never detected in cells with callose in the newly formed septae. Additional experiments verified that no fixation-induced artefacts occurred. Our results show that callose is a regular component of developing septae in juvenile cells during cytokinesis in multicellular green algae and embryophytes. The implications of our results with respect to the evolutionary relationships between extant charophytes and land plants are discussed. Received: 15 September 2000 / Revision received: 23 October 2000 / Accepted: 23 October 2000     

The diversity of bacteria,eukaryotic cells and viruses in an oligotrophic lake

An in situ transmission electron microscopic study of biomass samples concentrated from oligotrophic lake water revealed a variety of virus-infected microbial cells and many free viruses and virus-like particles. The most abundant group of microorganisms in screened and filtered water-column samples were 2 μm or less in diameter, and included representatives of several oligotrophic genera, Prosthecomicrobium, Ancyclobacter, Caulobacter and Hyphomicrobium. Among the prokaryotic host cells, which included both heterotrophs and autotrophs, on the basis of electron microscope observations, approximately 17% were infected with bacteriophage or bore adherent phage particles on their surfaces. Several bacterial morphotypes were observed among the prokaryotic hosts. Water samples passed through a 20-μm Nitex screen allowed us to concentrate and examine the larger host cells as well, including several species of single-celled algae and two amoeba species. The infected algal cells included those Chlorella-like in appearance, photosynthetic flagellates and others that could not be positively identified. About one-third of the eukaryotic cells were infected by viruses that were larger (150–200 nm) and structurally more complex than bacteriophages (50–60 nm). None of the viruses have been isolated, but when 0.2 μm filtrate from a biomass sample was spotted onto lawns of four representative heterotrophs and a Chlorella, the clearing observed was taken as evidence of lysis. Cyanobacterial lawns showed no plaques. Thin sections of two amoeba showed food vacuoles containing what appeared to be virus particles of a type seen in certain prokaryotic and eukaryotic cells in the biomass. Received: 26 January 1996 / Received revision: 10 July 1996 / Accepted: 5 August 1996     

Bacterial diversity assessment in soil of an active Brazilian copper mine using high-throughput sequencing of 16S rDNA amplicons

Mining activities pose severe environmental risks worldwide, generating extreme pH conditions and high concentrations of heavy metals, which can have major impacts on the survival of organisms. In this work, pyrosequencing of the V3 region of the 16S rDNA was used to analyze the bacterial communities in soil samples from a Brazilian copper mine. For the analysis, soil samples were collected from the slopes (geotechnical structures) and the surrounding drainage of the Sossego mine (comprising the Sossego and Sequeirinho deposits). The results revealed complex bacterial diversity, and there was no influence of deposit geographic location on the composition of the communities. However, the environment type played an important role in bacterial community divergence; the composition and frequency of OTUs in the slope samples were different from those of the surrounding drainage samples, and Acidobacteria, Chloroflexi, Firmicutes, and Gammaproteobacteria were responsible for the observed difference. Chemical analysis indicated that both types of sample presented a high metal content, while the amounts of organic matter and water were higher in the surrounding drainage samples. Non-metric multidimensional scaling (N-MDS) analysis identified organic matter and water as important distinguishing factors between the bacterial communities from the two types of mine environment. Although habitat-specific OTUs were found in both environments, they were more abundant in the surrounding drainage samples (around 50 %), and contributed to the higher bacterial diversity found in this habitat. The slope samples were dominated by a smaller number of phyla, especially Firmicutes. The bacterial communities from the slope and surrounding drainage samples were different in structure and composition, and the organic matter and water present in these environments contributed to the observed differences.     

Short term biotic response before and during the treatment of an acid mine drainage with sodium carbonate

The lower portion of Upper Three Runs, a woodland stream in central Pennsylvania, receives acid drainage from a strip mine. In 1974, the effect of this input on pH and benthic invertebrates was studied by Tomkiewicz & Dunson (1977). We sampled the same stations in 1986 and then treated the mine drainage with sodium carbonate for seven days in an effort to evaluate the short term colonization response of brook trout (Salvelinus fontinalis) and invertebrates. No differences in the pattern of pH and invertebrate distribution was found between the 1974 and 1986 results, although pH values and invertebrate densities were higher in 1986. Total number of invertebrates and number of taxa colonizing bricks during three pre-treatment time periods (8, 10, 18 days) did not differ from the single treatment period (7 days). However, two species of Baetis (Ephemeroptera: Baetidae) did increase in the treatment section during sodium carbonate application. The number of brook trout also increased in the treatment section, as compared to one pre-treatment estimate. These results indicate that motile species are able to respond within seven days, whereas, longer treatment may be required to produce community wide responses.Author to whom correspondence should be addressed     

Bacterial community shift along a subsurface geothermal water stream in a Japanese gold mine

Change of bacterial community occurring along a hot water stream in the Hishikari gold mine, Japan, was investigated by applying a combination of various culture-independent techniques. The stream, which is derived from a subsurface anaerobic aquifer containing plentiful CO₂, CH₄, H₂, and NH₄⁺, emerges in a mine tunnel 320 m below the surface providing nutrients for a lush microbial community that extends to a distance of approximately 7 m in the absence of sunlight-irradiation. Over this distance, the temperature decreases from 69°C to 55°C, and the oxidation-reduction potential increases from –130 mV to +59 mV. In the hot upper reaches of the stream, the dominant phylotypes were: 1) a deeply branching lineage of thermophilic methane-oxidizing -Proteobacteria, and 2) a thermophilic hydrogen- and sulfur-oxidizing Sulfurihydrogenibium sp. In contrast, the prevailing phylotypes in the middle and lower parts of the stream were closely related to ammonia-oxidizing Nitrosomonas and nitrite-oxidizing Nitrospira spp.. Changes in the microbial metabolic potential estimated by competitive PCR analysis of genes encoding the enzymes, particulate methane monooxygenase (pmoA), ammonia monooxygenase (amoA), and putative nitrite oxidoreductase (norB), also substantiated the community shift indicated by 16S rRNA gene analysis. The diversity of putative norB lineages was assessed for the first time in the hot water environment. Estimation of dominant phylotypes by whole-cell fluorescent in situ hybridization and changes in inorganic nitrogen compounds such as decreasing ammonium and increasing nitrite and nitrate in the mat-interstitial water along the stream were consistent with the observed transition of the bacterial community structure in the stream.     

Nutrient limitation of algal periphyton in streams along an acid mine drainage gradient

Metal oxyhydroxide precipitates that form from acid mine drainage (AMD) may indirectly limit periphyton by sorbing nutrients, particularly P. We examined effects of nutrient addition on periphytic algal biomass (chl a), community structure, and carbon and nitrogen content along an AMD gradient. Nutrient diffusing substrata with treatments of +P, +NP and control were placed at seven stream sites. Conductivity and SO₄ concentration ranged over an order of magnitude among sites and were used to define the AMD gradient, as they best indicate mine discharge sources of metals that create oxyhydroxide precipitates. Aqueous total phosphorous (TP) ranged from 2 to 23 μg · L^?1 and significantly decreased with increasing SO₄. Mean chl a concentrations at sites ranged from 0.2 to 8.1 μg · cm^?2. Across all sites, algal biomass was significantly higher on +NP than control treatments (Co), and significantly increased with +NP. The degree of nutrient limitation was determined by the increase in chl a concentration on +NP relative to Co (response ratio), which ranged from 0.6 to 9.7. Response to nutrient addition significantly declined with increasing aqueous TP, and significantly increased with increasing SO₄. Thus, nutrient limitation of algal biomass increased with AMD impact, indicating metal oxyhydroxides associated with AMD likely decreased P availability. Algal species composition was significantly affected by site but not nutrient treatment. Percent carbon content of periphyton on the Co significantly increased with AMD impact and corresponded to an increase in the relative abundance of Chlorophytes. Changes in periphyton biomass and cellular nutrient content associated with nutrient limitation in AMD streams may affect higher trophic levels.     

Microbial diversity in acid mine drainage of Xiang Mountain sulfide mine, Anhui Province, China

To understand the composition and structure of microbial communities in acid (pH 3.0) mine drainage (AMD) associated with pyrite mine tailings in Anhui Province, China, molecular diversities of 16S rRNA and 18S rRNA genes were examined using a PCR-based cloning approach. Bacterial, archaeal and microeukaryotic clone libraries were constructed. In contrast to typical dominance of autotrophic acidophiles, genus Acidiphilium, which consists of mixotrophic acidophiles capable of chemoorganotrophic and photosynthetic metabolisms, was the largest group in the bacterial clone library. These mixotrophic organisms may be advantageous in the oligotrophic AMD environment of the study site (certain amounts of dissolved organic carbon and light) by switching between two modes of metabolisms. Unexpectedly, a large fraction of bacterial clones (12.7%) were related to the neutrophilic genus Legionella, which can cause Legionnaires’ disease, a potentially lethal pneumonia. The eukaryotic 18S rRNA gene sequences were mostly related to Oxytricha, Nuclearia, and Penicillium. In the archaeal clone library, all the sequences were affiliated to the phylum Crenarchaeota, while the Euryarchaeota was not present.     

Biofilm and planktonic microbial communities in highly acidic soil (pH < 3) in the Soos National Nature Reserve,Czech Republic

Biofilm formation is a typical life strategy used by microorganisms populating acidic water systems. The same strategy might be used by microbes in highly acidic soils that are, however, neglected in this regard. In the present study, the microbial community in such highly acidic soil in the Soos National Nature Reserve (Czech Republic) has been investigated using high-throughput DNA sequencing and the organisms associated with biofilm life mode and those preferring planktonic life were distinguished using the biofilm trap technique. Our data show the differences between biofilm and planktonic microbiota fraction, although the majority of the organisms were capable of using both life modes. The by far most abundant prokaryotic genus was Acidiphilium and fungi were identified among the most abundant eukaryotic elements in biofilm formations. On the other hand, small flagellates from diverse taxonomical groups predominated in plankton. The application of cellulose amendment as well as the depth of sampling significantly influenced the composition of the detected microbial community.

     

Algal diversity in flowing waters at an acidic mine drainage “barrens” in central Pennsylvania,USA

Microscopic investigations were undertaken to decipher the diversity in the lotic algal communities from acidic waters (pH 2.4–3.2) flowing overland in sheets and channels at an acid mine drainage (AMD) barrens near Kylertown, PA, USA. Microscopic observations, supplemented with taxonomic keys, aided in identification of the dominant algae, and measurement of carbon from adjacent soils was undertaken. The unicellular protist Euglena sp. was most abundant in slower flowing waters (i.e., pool near point of emergence and surficial flow sheets), while Ulothrix sp. was most abundant in faster flowing water from the central stream channel. A diverse range of unicellular microalgae such as Chlorella, Cylindrocystis, Botryococcus, and Navicula and several filamentous forms identified as Microspora, Cladophora, and Binuclearia were also recorded. The observed high algal diversity may be related to the long duration of AMD flow at this site which has led to the development of adapted algal communities. The comparatively higher carbon content in soil materials adjacent to slower flowing water sampling locations provides evidence for the important role of algae as primary producers in this extreme environment.